A2141 - No Power and 20V + 5V

e1ysion

New member
I have an issue with my A2141 MBP 16" 2019.
I replaced the battery and while finalizing reassembly, I did not disconnect it.

Issue:
No power, 20V 0,02A on left USB-C side and 5V 0,025A on right USB-C side

I followed this guideline:

And measured the resistance of C9586 and get 50 kOhms, is that high? Should I remove it?

Sorry, I am a beginner, help is appreciated. I also don't know where to measure PPBUS_G3H or where I should begin.

WhatsApp Image 2025-08-08 at 00.09.28_2196648a.jpgPXL_20250807_213031286-min.jpgPXL_20250807_213040320-min.jpgPXL_20250807_220942890-min.jpg

Thanks much in advance
 
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e1ysion

New member
Update: It's 5V on all ports, my bad.
I went with this:

Check voltage on PPBUS_G3H
Shows 12.3V

Check voltage on PP3v3_G3H_RTC_X
Shows 3.3V

Check voltage on PP3v3_G3H_SOCPMU
It shows 0.835V

R7900 Measures:
3.379V One side
2.09V Other side

While measuring, I bridged R7900 to C7908 🤦‍♂️🤦‍♂️
C7908 shows 2.09V (PP3V3_G3H_PMU_VINRTC_R)

R7900 looks visibly damaged, discoloured (from what I see with my bare eyes, at least) but I couldn't feel any high temp.

What should I do?

UPDATE2: The USB-C Power Meter jumps to 17V, shuts down and reboots, then shows 5V negotiated

PXL_20250808_004354913.MP.jpg
 
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2informaticos

Administrator
Staff member
First of all, welcome to the forum!

Get a proper multimeter probes, to avoid future damages.

Be sure R7900 is still good (0 ohm).

"USB-C Power Meter jumps to 17V, shuts down and reboots, then shows 5V negotiated"
All 4 ports have the same behavior?

Is the battery data cable connected?
Also be sure to tight the battery screw correctly.
Be aware, this machine requires 96/140W charger.
 

e1ysion

New member
First of all, welcome to the forum!

Get a proper multimeter probes, to avoid future damages.

Be sure R7900 is still good (0 ohm).

"USB-C Power Meter jumps to 17V, shuts down and reboots, then shows 5V negotiated"
All 4 ports have the same behavior?

Is the battery data cable connected?
Also be sure to tight the battery screw correctly.
Be aware, this machine requires 96/140W charger.
Thank you very much, happy to be part of the community :)

Will order the probes!
Yes, the behavior happens on all ports, but the battery is not connected, this happens with the bare board with only one USB-C port connected
 

e1ysion

New member
Edit: Sorry, didn't finish my sentence.
Battery is not connected, as the board is out. Should I connect it?

R7900 shows 1.5M ohms
 

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2informaticos

Administrator
Staff member
Replace R7900, is burnt; it is 0 ohm resistor!
First be sure no short over C7907...

BTW, write directly into bottom reply box, instead of clicking Reply button.
I don't see any reason to quote an entire post, visible few centimeters above.
Please, maintain forum aesthetic.
 

e1ysion

New member
Replaced the resistor, same behavior.
Pin 1 of R7900 is shorted to ground (RTC-X). Is this thing toast?

EDIT:
RTC-X is 3.38V
C7907 is not shorted
 
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